Refrigerating system



April 20, 1943. o, c. IRWIN REFRIGERATING SYSTEM Filed Sept. 12, 1932 3 Sheets-Sheet 1 A OE 4 Q i y 2 w 3 S H 1 3 3 3 5.

O, C. IRWIN REFRIGERATING SYSTEM April 20, 1943.

Filed Sept. 12, 1932 3 Sheets-Sheet 2 IIIIIVI IIIIIIIIIII r/ IIIIIIIIIIIIIIII IIIIIIIIII/IIIIIIIIIIIIIIIIIIIIIIIIII R Y m m m v w m- A m April 20, 1943. o. c. IRWIN 2,316,791

REFRIGERATING SYSTEM Filed Sept. 12, 1932 3 Sheets-Sheet 3 INVENTOR 0/1ver C. rwn

' ATTORNEY Patented Apr. 20, 1943 REFRIGERATING SYSTEM Oliver 0. Irwin, New York, N. Y assignor by meme assignments, to 8 Cap and seal corporation, Chicago, 111.. a corporation of VI!- Application September 12, m2, Serial No. 032,140

GClaims.

of the invention will be applicable to refrigerated motor trucks and other units of mobile transportation.

Heretofore, railway cars have been cooled by the time honored ice and salt method or by the use of evaporating chemicals or by the use of mechanical refrigeration machines wherein the motor, compressors, condenser, evaporator, etc., are all carried by the car.

These former systems have many disadvantages such as the matter of weight, unreliability in emergencies, unreliability of mechanically moving parts, etc. and etc.

It is one object of my invention to provide a system of refrigeration for mobile units wherein there are no moving parts on the unit.

It is another object of myv invention to provide such a system wherein the weight of apparatus and refrigerant becomes a negligible factor in the total weight of the mobile unit; and likewise wherein the useful load carrying space occupied by the refrigerating equipment is also a negligible 'part of the total useful space of the unit.

The foregoing objects of my invention are in part accomplished by the particular system and improvements hereinafter disclosed and in part by the particular apparatus used on the mobile unit. As to the refrigerating system used, it is basically an absorption system. However, the absorption system in my case is divided into a plurality of aunits.

It is a further object of my invention to provide an absorption system wherein the total refrigration cycle is performed in separate places.

It is a still further object of my invention to provide a system of mobile refrigeration using the absorption cycle wherein a portion only of the cycle is performed on each mobile unit.

It is an even further object of my invention to provide a system of mobile refrigeration wherein a portion of an absorption cycle of refrigeration is performed on each mobile unit and a plurality of such units cooperate with a central depot wherein the remainder of the absorption cycle of refrigeration is performed.

it is an even further object of my invention to provide a system of mobile refrigeration wherein the refrigerant used on the mobile unit is precooled.

It is still another object of my invention to provide a system of refrigeration using the absorption cycle wherein the absorber is used to pro-cool the condensed refrigerant.

It is still another object of my invention to provide a system of mobile refrigeration wherein extensive use is made of finned surfaces on the mobile unit.

It is still another object of my invention to provide a system wherein the control of the temperature of the mobile unit is governed by the pressure in the refrigerant supply tank.

It is an even further object of my invention to provide a cooling arrangement for mobile units using an absorption system of cooling and an air circulatory system.

Other and further objects of my invention will be apparent from the following description taken in conjunction with the accompanying drawings, wherein- Figure l is a diagrammatic layout of so much of a refrigerating system and apparatus as is located at the central depot;

Fig. 2 is a diagrammatic illustration of the bodyportion of a railway car, parts being broken away and parts being shown in section to facilitate the illustration of the application of my invention thereto; mg'lg. 3 is a vertical section on the line 3-3 of Fig. 4 is a partial top plan view of refrigerating mechanism taken with the top of the car body removed;

Fig. 5 is a vertical section of an automatic control valve;

Fig. 6 is a diagrammatic illustration of a portion of a railway car with a modified arrangement of cooling surface; and

Fig. 7 is a diagrammatic illustration of a railway carwith a modified form of refrigeration mechanism applied thereto and utilizing the principle of circulating cooled air.

In absorption type refrigeration machines, the cycle of the process of producing cold may be stated as follows: There is introduced into a generator or still a liquid which is a combination of a refrigerant and an element in which the liquid is absorbed-respectively ammonia and water usually. Heat is applied to the generator sufllclent to boil ed the refrigerant whic passes into a condenser in the form of a vapo The condensed refrigerant in turn to an expander or evaporator. Here the refrigerant is again vaporized and absorbs the heat from the air or other medium surrounding the evaporator.

The refrigerant leaves the evaporator and is returned to the generator, but interposed between the GVBDOI'.st()l' and generator is an absorber. The absorber contains the so-called weak liquor (the residue from the generator after the refrigerant is boiled oil) and into the absorber is also introduced the refrigerant coming from the evaporator. The two units and thus the liquor leaving the absorber for the generator is a strong liquor, by which is meant a liquor containing a strong charge of refrigerant or ammonia.

Of course, there may be various other elements introduced into this simple system such as a heat exchanger and a pump for getting the liquid from the absorber into the still, etc.

One step of my invention contemplates placing on the mobile unit only so much of the apparatus of an absorption system as is necessary to do the work of cooling the mobile unit, and leaving for a separate, detached and probably stationary central unit all that apparatus having to do with the reclamation and regeneration of the refrigerant. As it is shown and described in the instant application, my system contemplates having each railway car equipped with an evaporator fed from a storage tank of refrigerant, the vaporized or expanded refrigerant being collected in a second storage tank. This is all of the mechanism that is needed for actual cooling of the railway car because it is the vaporizing or expanding of the refrigerant which accomplishes the act of cooling. At centralized points along the railway system will be depots at which will be located the reclamation portion of the absorption system, namely, the generator, con denser, absorber and related elements. When a railway car is to begin its run from one of these central depots, anhydrous ammonia is introtroduced into one storage tank and weak liquor is introduced into the other storage tank in bebetween which is the evaporator. Only so much charge is introduced as has been predetermined to be suillcient for the particular intended run plus whatever amount is determined upon as a safety factor.

At the end of the run there will be located another of these central depots. when the railway car reaches that point detachable hose connections will he made to the respective storage tanks on the railway car and the contents thereof umped out and into appropriate storage tanks at the central depot. The car can then be refilled and sent on its way immediately. At the central depot the charge received from the railway car is passed into the generator where the refrigerant is boiled 08, passed into a dehydrator, and into a condenser, the anhydrous ammonia passing directly into storage tanks. The weak liquor goes from the generator to the heat exchanger and from the heat exchanger into a weak liquor storage tank. Please note that certain details of the system. are not referred to in this general description but will be brought out herelnafter.

more fully hereinafter. It is at once apparent that anything that reduces the amount of refrigerant that has to be carried upon the railway car is advantageous both from the standpoint of space occupied and weight carried.

Referring to Fig. l of the drawings, which shows in outline so much of my absorption refrigeration system as is intended to be located at the central depot, a generator is indicated at H. The source of heat in the generator is a coil of pipe not shown but having the ends thereof respectively connected to the inlet pipe I: and the outlet pipe II that are in turn connected to the boiler ll of a steam heating plant It. It indicates a steam trap and il a shut-off valve, all of which construction and arrangement is usual and well known.

The strong liquor to be regenerated is supplied to the generator H from the pipe II in a manner hereinafter described. The heat in the steam coil in the generator ii is sui'ilcient to boil oil the ammonia, the refrigerant referred to by way of example, and the ammonia vapor thus produced leaves the generator through the pipe ll, entering the dehydrator II. The purpose of the dehydrator is to remove any water vapors that may pass from the generator through the pipe I 8. Any form of dehydrator may be used and for purposes of illustration I have shown a dehydrator that condenses the water vapors and returns them to the generator. The dehydrator 2| is water cooled, the water circulating cells (not shown) in the dehydrator being connected to the inlet and outlet pipes 22 and 23 respectively that are in turn connected to a source of water supply. The water that is condensed in the dehydrator is returned to the generator through the return line 24 which contains strap 25 to prevent the escape of vapors from the generator through the condensed water, the dehydrator being tipped at an angle as shown.

The ammonia vapors leave the dehydrator through the pipe 26 and enter the condenser 11. The condenser is also water cooled, the coils in the condenser being supplied with a circulating cooling water through the inlet and outlet pipes 28 and 20. In the condenser the ammonia vapors are completely condensed and leave the condenser through the pipe II entering one or the other of a pair of storage tanks 82, 33, depending upon the condition of the valves 34 and I! respectively.

Returning to the generator H, after the ammonia has been boiled oil. the strong liquor and the ammonia vapors have passed on, that which remains is what is known as a weak liquor. The weak liquor is water containing a small percentage of ammonia. The weakest liquor is of course at the bottom of the container II and this is removed from the generator through the pipe it which communicates with a heat exchange 31. The heat exchanger 31 is of the well'known tubular construction, the weak liquor being introduced into the shell and circulating through the exchanger about the tubes. The heat exchanger function will be described in the following paragraph. The partially closed weak liquor leaves the shell of the heat exchanger l'l through the pipe 3! and enters the weak liquor storage tank and cooler 38.

The strong liquor to be regenerated (received from the trucks) is stored in the tank ll and when it is to be regenerated is withdrawn from the tank I through the pipe I by means of the pump 43 :which introduces this strong liquor into lino tubular portion of the heat exchanger :1 throughthepipe u. Thereasonforthlsisthat it is desirable from the standpoint of economy of operation to have the strong liquor as hot as possible when it is introduced into the container II and by circulating the strong liq r through the heat exchanger in contact with the hot weak liquor that comes from the generator it is heated and the weak liquor is cooled on its way to its storage tank and cooler. The stron liquor leaves the heat exchanger through .the pipe 48 which communicates with the inlet pipe. 08 leading into the generator ll.

Reeapitulating, the complete cycle involves the circulation of the strong liquor from the storage tank Ii through the pump it and the heat exchanger 31 to the generator II where the ammonia is boiled off, the ammonia vapor passing through the dehydrator 2i into the condenser 21 and the anhydrous ammonia passing from the condenser 21 to one or the other of the storage tanks 82, 38. The weak liquor leaves the generator ll, circulates through the heat exchanger I1 and is stored in its storage tank a.

The regeneration or reclamation of the refrigerant is now completed and the refrigerant in the storage tanks 32 and SI and the weak liquor in the storage tank I! are now ready for use in doing the work of cooling but, as explained above, this portion of the refrigerating cycle is accomplished on the railway car or mobile unit as will be hereinafter described.

I have heretofore referred to the use of precooled materials on the railway car. By precooling the refrigerant is meantlowering the temperature thereof by the amount necessary to bring the temperature of the refrigerant itself down to or below the temperature at which it is desired to maintain the unit to be cooled. This is sometimes referred to as the heat of the liquid which indicates the heat that it is necessary to take from one pound of liquid refrigerant in order to lower it from the temperature at which it is fed to the expansion valve to the temperature at which it boils in the evaporator. For example, if it is desired to start with a pound of liquid ammonia at 75 F., and heat is to be taken therefrom, at -26 F., then the body of ammonia must first be cooled to'that point.

By precooling the liquid in the central refrigerating plant, to the 25 F. point or below, and feeding that pro-cooled refrigerant to the railway car, it is at once apparent that only "so much liquid refrigerant need be placed upon the railway car as is necessary to do the work of bringing the temperature of the railway car down to -25", and maintain the railway car at this point over the predetermined period. Thus, the railway car is not called upon to provide either the space for nor carry the load of that amount of ammonia used to lower the temperature of the body of refrigerant down to the point of useful work, namely -25 F.

In my improved system shown in Fig. l, I precool the ammonia in first one and then the other of the storage tanks 32 and 33. It will be assumed that the ammonia in tank 32 is being preoooled in which event the valve 46 will be opened and the valve 1 closed. Ammonia gas or vapor will be taken from the tank I! through the pipe 48 to the absorber l8. Weak liquor is also introduced into the absorber 49 from the heat exchanger 31 through the pipe iii, it being necessary to adjust the valves II in pipe II and the valve in pipe 50 to divide the path of the weak nia remaining in the tank I! is cooled to what-' ever temperature is desired, say 50 F. At that time the valve 40 will be closed and the valve 41 will be opened, whereupon the same operation will be repeated to pre-cool the onia in the tank I3. Of course, the valves 84 and SI will be adjusted accordingly. It will be noted that the storage tanks 32 and 13 are enclosed by a'thick I casing of insulation 5!.

Normally, in prior art systems, the absorber is located between the evaporator and the still or generator. The weak liquor from the still passes into the absorber from one side and from the other side there is introduced the ammonia returning from the evaporator or cooling element which ammonia is absorbed in the weak liquor converting it to a strong liquor. The strong liqnor is then returned to the still where the ammonia is boiled on and the cycle is repeated as heretofore described.

There also may be introduced between the still and the absorber a heat exchanger which receives the hot weak liquor directly from the still, the

' weak liquor that goes to the absorber being in that case taken from the heat exchangenwhile circulating through the interior of the heat exchanger is the strong liquor coming from the absorber, which being brought into heat exchanging relation with the hot liquor from the still raises the temperature of the strong liquor prior to its being introduced into the generator or still thereby reducing the work of the generator.

It will be apparent from the foregoing description that the heat exchanger 31 is functioning as in the normal absorption cycle but that the function of the absorber I! is diflerent in my proposed cycle. However, other means may be used to pre-oool the ammonia or refrigerant. For example, reference is made to my copendlng application, Ser. No. 632,741, flied concurrently herewith.

In my proposed system I also contemplate precooling the weak liquor which is also supplied to the railway car. For this purpose the weak liquor storage tank 38 is provided with a water cooling system the inlet and outlet pipes of which are indicated at it and 51 respectively. Also, the weak liquor storage tank is entirely enclosed by heat insulation indicated at 58.

The foregoing completes the equipment to be located at the central depot. Of course, it is entirely conceivable that this depot would be a small plant that would regenerate the charge from one railway car at a time and discharge the reclaimed refrigerant into the same or the next car which would make unnecessary the storage tanks referred to above.

The description will now proceed to the equipment for the railway car. Referring to Figs. 2, 3 and 4, the body of a railway car is diagrammatically indicated at ll, as having a separate compertinent 62, at either or both ends of the railway car II. The compartment 82 contains a pair of tanks 88 which are intended to be filled at the central depot with weak liquor through the connection 88 that is controlled by the shut-off valve 88. The tanks 88 are interconnected by a plurality of cross pipes 88. It will be noted that tanks 88 are provided with finned surfaces indicated at 81 and that the connecting pipes 88 are provided with flnned surfaces 88 which assist in the air cooling of the tanks and connecting pipes. Whether the compartment 82 is a closed of! space on the inside of the body of the car or a separate compartment outside of the body of the car as indicated at 82 is immaterial. For the purposes of securing air circulation the end wall 88 is provided with louvres II through which the air passes into the compartment 82. Outlets or ventilators for the air are indicated at I2, each having a forward and rear opening covered by pivoted leaves or flaps I8 that close under the pressure of the air from the direction of travel but are free to open in the opposite or rear direction to allow the escape of air from the compartment 8!.

Mounted on the interior of the car are a pair of tanks I8 of smaller capacity than the tanks 88, the tanks being vertically disposed in the respective corners of the car so as to occupy the least amount of useful load carrying space and being adapted to contain the refrigerant used.

A number of different arrangements may be provided for cooling the interior of the car. Qne such arrangement is shown in Figs. 2, 3 and 4 wherein the tanks I8 are interconnected by means of a series of horizontally extending pipes 11 that are provided with finned cooling surfaces I8. The tanks I8 are contained in a separate compartment formed by the vertically disposed bunker wall I9 having one or more openings 88 at the bottom thereof and being open at the top. Without for the moment defining the connections between the tanks and the cooling coils, it will be apparent that air will circulate through the openings 88 into the compartment containing the tanks I8 and associated pipes, upwardly thereover, and thence out into the car.

The tanks I8 are intended to be filled at the central depot with pre-cooled refrigerant through the connection BI controlled by the valve 88.

Regulation of the temperature of the car is controlled in a unique manner. The refrigerant tanks I8 are interconnected by means of the pipe 88, which communicates with a pipe 88, a valve 88, and the pipe connection 88. The valve may be of any ordinary construction suitable for the purpose. One such valve is illustrated in detail in Fig. wherein the valve is closed by the disk 81 carried by plunger 88 against which spring 89 presses, the tension of the spring being adjustable by means of the screw 88.

The temperature maintained in the car is directly proportional to the pressure existing in the tanks I8 and cooling pipes 11. It will be assumed that a fifteen pound pressure will maintain a zero temperature in the car and that this is the desired temperature. The cooling apparatus will continue to function and heat be extracted from the air circulating over the cooling surfaces I1, 18. When the pressure in the cooling system exceeds fifteen pounds, the valve disk 81 will be forced downwardly permitting the accumulated vapor and gas in the cooling system to escape through the pipe 88 into the absorber system of tanks 83 and pipes 88. when the pressure has been lowered to fifteen pounds. the valve disk closes under the action of the spring and thus the temperature ofthe car is maintained at a fixed level.

The functioning of the apparatus on the railway car may be described as follows: with the tanks 88 and I8 fllled respectively with pro-cooled weak liquor and pre-cooled refrigerant, the refrigerant begins to boil off of the body in the tanks 18 and through the cooling coils in accordance with the requirements to reach and maintain the desired temperature in the car. The spent gas leaves the cooling coils and escapes into the weak liquor or absorber tanks 88 where it Is absorbed and retained until the liquor is drawn of! at the central depot.

In other words, the only portions of the absorption cycle that are accomplished on tlile raflway car are expansion or evaporation and absorption-only what is necessary in the step of cooling. All of the other steps of the refrigerating cycle are performed at some other point. The resultant advantages in the operation of a plurality of refrigerated railway cars are obvious.

When the railway car reaches the central depot the flexible hose IN is connected to the outlet connection 88 of the tanks 88, any well known form of leak-proof connecting nozzle being used for this purpose. There may or may not be a pump inserted in this line, depending upon the relative heights of the railway car and central plant or of the relative pressures between the tanks 88 on the railway car and the tank 8| in the central depot. It may be explained at this point that during the course of the run of the railway car what was weak liquor in the tanks 83 at the beginning of the run has now become strong liquor by reason of the absorption of the spent gases from the cooling coils. This now strong liquor is transferred to the storage tank 8| after the valves 88 and I82 are opened. I

At the same time the flexible hose I88 is connected to the outlet connection 8| on the tanks 18, the same manner of connection being eifected. Also a pump may or may not be included in this connection line. Then upon opening the valves 82 and I88 and one or the other of the valves I88 and I88 the unspent charge of liquid ammonia or refrigerant, if any, in the tanks 18 is drawn off the railway car and stored In one or the other of the storage tanks 82, 88.

The railway car is then ready to be re-fllled so as to continue its run. This is done by detaching the hose connection I8I from the outlet connection 8| and attaching thereto the flexible hose connection I81 leading from the weak liquor storage tank 88. This connection line may or may not include a pump. Upon opening the valve I88 the tanks 88 are fllled with pre-cooled weak llquor from the storage tank 88. When the desired charge has been put into the tanks 88, the valves 85 and I88 are shut oil and the flexible hose connection I8! is detached. The flexible hose connection I88 remains connected to the outlet 8|, and if the valve I88 has been opened when the unspent charge has been taken from the railway car it is now closed and valve I88 is opened. The pump, if used, is reversed and the pre-cooled charge in the storage tank 32 is inserted into the storage tanks I8 on the railway car. As soon as the required charge has been made, valves 82 I88 and I88 are closed, the flexible hose connection I88 is detached and the railway car is now ready to continue its run with a fresh charge of cooling agents,

A modified arrangement of cooling surfaces is shown in Fig. 6. In this flgure, one or more tanks 9i are intended to hold the charge of precooled refrigerant corresponding to the tanks 1-6 of Fig. 2, and one or more tanks 02 are intended to hold the charge of weak liquor, the same as' tanks 83 of Fig. 2. In this figure, the cooling surfaces are provided by a set of roof coils 03 and one or more side wall coils Q4. The roof coils are separated in a separate compartment by the partition wall II. The coils II and 94 may be interconnected or may be independently supplied with refrigerant from the tanks II but in this figure they are intended to be shown interconnected, and fed from the supply pipe 8| having expansion valve 91 therein. The supply pipe 96 is not shown connected to the coils II and 94 because they are broken away. The point of connection is at a distance removed from the absorber tanks 92. The expanded refrigerant passes through the coils 93, 94, is vaporized in absorbing the heat from the interior of the car and passes out of the coils through the return line indicated at 98 and which extends into the absorber tanks 92. If desired, the top of the tanks 9i may be vented to the return line through the valved connection 8! as shown.

Otherwise, the car portion of the entire refrigeration system is charged, emptied, and functions as described above in connection with Figs. 2, 3 and 4. A further modified system and arrangement of cooling tanks is shown in Fig. '1. In this figure, the railway car is diagrammatically illustrated at iii. Mounted inside of the car and in one end thereof is one or more tanks 2 intended to be filled with pre-cooled liquid ammonia through the connection H3 controlled by the valve Ill. The tank H2 is in communication with the coils of an air cooling unit Iii through the valve H6 and associated piping. This latter unit may be of any well known construction, that shown in the drawing being for purposes of illustration only. The return line for the gases spent in the air cooling unit is indicated at I", this pipe extending down the end wall of the car and along the bottom into communication with one or more tanks H8 and H9 respectively arranged longitudinally and transversely of the railway car. These tanks are provided with finned cooling surfaces as indicated at I20 and are the weak liquor storage or absorber tanks equivalent to the tanks 63 of Figs. 2 to 4. They are intended to be filled with weak liquor through the valved connections I22. It will be noted that the tanks Ill and H9 are disposed underneath the car body iii. The tanks may or may not be provided with a plurality of internal splash guard plates llfl. which are perforated for the passage of the liquid therethrough.

The bunker wall or'partition I23 divides the cooling equipment off from the remainder of the car interior. However, the bunker wall I23 does not extend entirely to the bottom or to the top of the car, allowing for the circulation of air thereabout. Mounted within the air cooling unl't H is a fan I24, the prime mover of which is indicated at I25. The prime mover in this case may be an electric motor or may be, as indicated, an air motor connected to the compressed air lines of the train through the pipes I26 and ill.

When the tanks 8, HI and "2 are filled as heretofore described at the central depot, and the fan i operates it circulates the air through the body of the car, through the compartment in back of the bunker 'wall I28 and through the air cooling unit iii, where the air is cooled. This circulation of cold air serves to refrigerate the interior of the car iii. The circulation of warm air past the unit ill vaporizes the refrigerant, the spent gases leaving the radiator of the air cooling unit ill and becoming absorbed in the liquor in the tanks III, III. when the car returns to the central depot the tanks III. III and ill are emptied and may be refilled as described above.

It will be apparent from the foregoing description that I have provided a system of mobile refrigeration which involves no moving parts and a minimum of apparatus on the mobile unit together with a new and improved system of handling a plurality of such mobile units. Furthermore, the system of charging and regulating the temperature of the railway car is simple and efiicient.

Modifications may be made in the arrangement and location of parts within the spirit and scope of my invention, and such modifications are intended to be covered by the appended claims.

I claim:

1. A refrigerated power-moved unit comprising a body having cooling apparatus therefor comprising only an evaporator of an absorption refrigeration system mounted in the body and arranged to cool the interior thereof, the evaporator comprising two spaced apart refrigerant holding tanks, a plurality of pipes provided with finned cooling surfaces interconnected to said tanks, an absorber carried by said body and connected to the evaporator, and means for air cooling the absorber.

2. A refrigerated power-moved unit comprising a body, an evaporator of an absorption refrigeration system mounted in the body and havin refrigerant storage capacity, an absorber for the spent refrigerant mounted outside said body, a pipe connection from the evaporator to the absorber, and means for regulating the temperature of said body in accordance with the pressure in said evaporator.

3. A refrigerated mobile transportation unit comprising a body having cooling apparatus therefor comprising only an evaporator of a absorption refrigeration system containing refrigerant and mounted in the body, an air cooling unit including a radiator connected to the evaporator, a fan directing 'air through the air coolingunit, a motor for driving the fan, and an absorber carried outside said body and connected to the air cooling unit to receive the spent refrigerant therefrom.

4. A refrigerated mobile transportation unit comprising a body, an evaporator of an absorption refrigeration system containing refrigerant and mounted in the body, an air cooling unit including a radiator connected to the evaporator, a fan directing air through the air cooling unit, an air driven motor for rotating the fan, connections from the motor to a source of air supply under pressure, and an absorber carried outside said body and connected to the air cooling unit to receive the spent refrigerant therefrom.

5. A refrigerated unit comprising a body, an evaporator of an absorption refrigeration system mounted in the body and having refrigerant storage capacity, an absorber for the spent refrigerant mounted outside said body, a pipe connection from the e yaporator to the absorber, and a regulator valve mounted in said pipe connection so as to regulate the temperature of said body in accordance with the measure in said evaporator.

6. A refrigerated power operated transportation unit comprising a body having mounted thereon only a atoreze tank for condensed refriaerent and mounted in the body, an air coolin: unit includin: a radiator connected to the storage tent and into which the refrigerant puaeeetandirectingeiroverthecooung unit. end an absorber curried outside said body end ccnnectedtotheeircoolinxunittoreceive the 5 spent refrigerant therei' OLIVER C. IRWIN. 

